Feed water regulating valve



1933- H. J. MASTENBROOK 1,938,602

FEED WATER REGULATING VALVE Filed Sept. 27, 1950 Jwmmtoc Patented Dec. 12, 1933 PATENT OFFICE FEED WATER REGULATlNG VALVE Henry J. Mastenbrook, Cleveland, Ohio, assignor to The Swartwout Company, Cleveland, Ohio, a

corporation of Ohio Application September 2'7, 1930 Serial No. 484,818

19 Claims.

This invention relates to feed water regulation and more particularly to the construction and control of a novel feed water regulator valve.

It is among the objects of my invention to provide feed water regulation which will take into account and compensate for or adjust itself to changes in boiler water level, changes in boiler load and variations in pump pressure. Another object is to provide a feed water regulating valve primarily positionable in accordance with boiler conditions and secondarily positionable inversely as the fluid pressure drop across the valve whereby the flow through the valve will tend to remain constant regardless of varying pressure drops across the valve as a consequence of varying header or pump pressures. A further object is to provide a valve having a closure member acted upon by two separate agencies, one responsive to boiler conditions and the other responsive to the fluid pressure drop across the valve. A further object is to provide means responsive to changes in certain other boiler conditions for modifying the effect of the fluid pressure drop on the movement of the valve closure member. A still fur-- ther object is to provide means for throwing the feed water valve wide open in the event of serious need for water in the boiler.

Another object of my invention is to modify the action of the feed water valve in response to changes in boiler load. In this regard a more specific object is to vary the effect of the agency reflecting pressure drop across the valve according to changes in boiler load while a continuous feed is maintained varying in response to changes in boiler water level.

Other objects will appear from the following detailed description of a preferred form of my invention, reference being had to the accompanying drawing. The essential characteristics are summarized in the claims.

In the preceding paragraphs and throughout the remainder of the specification I use the term boiler conditions to refer to boiler pressure, boiler temperature, rate of evaporation, boiler load, for boiler water level among other things. In the drawing, however, devices that are sensitive to boiler conditions, such as load and water level, have been shown. In the appended'claims this term refers to any one of these conditions unless, however, this term is modified in such a manner as to refer specifically to one of these conditions.

In the drawing the figure depicts a layout partly diagrammatic illustrating the feed water valve and control apparatus in operative relaw tion to a steam boiler.

Referring to the drawing, I have illustrated a boiler having a drum D in which it is desired to maintain a water level about along the line L-L. A feed water line 1 leads to the boiler through feed water valve 2. Steam flows from the boiler through a superheater S thence through the steam outlet pipe 3.

The feed water valve 2 is primarily controlled in response to changes in boiler water level through a pressure generator 4 mounted on a conduit 5 which spans the boiler water level and communicates with the steam and water spaces respectively. A conduit 6 leads from the pressure generator to the diaphragm chamber '7 of the feed water valve whereby varying pressures are established in this diaphragm chamber. to vary the opening of the feed water valve, all of which may be generally in accordance with the well known teaching of the Copley Patent No. 1,193,125 issued August 1, 1916.

The feed water valve insofar as itfollows the usual construction, has a body part 8 in which are carried suitable seats 9 which are cooperable with a balanced closure member 10. According The foregoing elements are of coursewell known and appreciated in the art and itmay be briefly summarized by saying that the lowering of the water level causes an increase in pressure to be generated in the generator 4, which increases the pressure in thediaphragm chamber 7 and moves the closure member 10 downwardly, increasing the opening of the valve whereby a greater flow of feed water is permitted, thereby replenishing the water level.

To vary the position of the valve closure member in response to other changes in operating conditions, a piston 21 is connected to the 'valve closure member through a stem 22, shown as depending therefrom. This piston moves in 'acylinder 23 which is secured to the valve body and the upper side of the piston is freely subjected to the valve outlet pressure. At the lower and remote end of the cylinder, fluid communication is established between the underside of the piston and other points of fluid pressure; a short conduit 24 leading therefrom.

The conduit 24 is connected through a T-connection to conduits 25 and 26. The flow of fluid through which conduits is controlled by valves 27 and 28. The valve 27 is in turn connected by a conduit 29 to the outlet side of the feed water valve. The valve 28 communicates with atmosphere at the point 30 and with the high pressure or inlet side of the feed water valve through the conduit 31. A needle valve 32 is disposed in the conduit 31 for the sake of controlling the flow therethrough and preferably a check valve 33 is placed in the conduit 29 to permit the flow of fluid only in the direction toward the low pressure side of the feed water valve.

The valve 28 is preferably and in all respects similar to that shown in my copending application, Serial No. 451,560, filed May 12, 1930 and may be described briefly as a pilot valve having a closure member 34 movable between seats 35 and 36, of which the seat 36 is longitudinally adjustable. The closure member is moved by a valve stem 3'7 and when the closure member engages the seat 36, communication through the conduit 31 is closed while communication through the seat 35 and the port 30 is opened. The closure member may assume intermediate positions permitting a flow through both seats and ports and of course may seat in its lower position closing communication through the port 30 to atmosphere. An adjustable spring 38 tends to force the closure member into its lowermost member from its lowermost position through intermediate positions into its uppermost position.

The diaphragm chamber is connected to the pressure generator 4 through an extension 5' of the conduit 6, so that like fluid pressures are maintained in the diaphragm chambers 7 and 40. The synchronism or sequence of movement between the closure member of the feed water valve and the closure member of the pilot valve is established according to the adjustment of the springs of those valves; due consideration being given to the effect of the piston 21 on the movement of the feed water valve.

The operation of this phase of my inventionmay be described briefly as follows, having for the moment no regard to the efiect of the valve 27. Presuming the feed water valve to be par-- tially opened so that the flow of feed water main-- tains a desired water level in the boiler for a given load, and presuming that the spring 38 of the pilot valve is set to maintain the closure member of the pilot valve in its lowermost position in opposition to the pressure in its diaphragm chamber 40, then there will be free communication through the conduits 24, 26, the pilot valve and conduit 31 (presuming the needle valve 32 to be opened a desired amount). This will establish header or pump pressure on the lower side of the piston 21 tending to close the feed water valve in opposition to boiler pressure or outlet pressure on the top side of the piston 21. Now if the pump pressure were to suddenly increase, the fiow through the feed water valve might be undesirably increased, except for the fact that this increase in pressure would be reflected on the lower side of the piston 21 tending to close the feed water valve and restrict the flow therethrough. In other words, the pressure drop across the feed water valve is measured on opposite sides of the piston 21 and any change in this drop causes a movement of the closure member of the feed water valve to compensate for the change in fluid pressure drop, either by increasing or decreasing the opening through the feed water valve. Thus if the pressure ahead of the feed water valve falls, the pressure on the lower side of the piston 21 also falls with the result that the closure member 10 moves downwardly affording a greater opening through the feed water valve to compensate for the decreased pressure drop across it. This phase of the operation may be summarized by saying that for a given pressure in the diaphragm chamber '7, i. e. a given water level in the boiler, the rate of flow of feed water will be maintained substantially constant regardless of varying drops in pressure across the feed water valve.

To supplement this control and to cause a greater flow of feed water than that described above, the pilot valve 23 is called into operation. In the simplest manner of its operation the seats 35 and 36 may be set relatively close together so that when the boiler water level falls to a predetermined point the pressure in the chamber 40 will be such as to move the closure member 34 of the pilot valve from its lower seat to its upper seat bleeding the chamber below the piston 21 to atmosphere through the conduits 24, 26, the pilot valve and the pilot valve port 30. The lower side of the piston 21 being relieved of all but atmospheric pressure will permit the feed water valve or cause the feed water valve to become wide open, thereby permitting enough flow of feed water to take care of any emergency.

The above manner of operation of the pilot valve may be modified very considerably by increasing the distance between the seats 35 and 36 so that a substantial and material travel is afforded for the closure member 34, which according to the characteristic of the spring 38 may take place during a considerable range of variation in pressure established in the diaphragm chamber 40. When the seats are so spaced and the pilot valve has this characteristic, a gradual increasing pressure in the chamber 40 due to a gradual lowering of the water level in the boiler, will cause the closure member 34 to move to an intermediate that while the pilot valve 28 is assuming an intermediate position the effect of the pressure drop 1 control on the piston 21 and on the opening of the feed water valve continues, however it may be modified by the action of the pilot valve.

To further control the regulation and to supplement the control described above, or to act independently of it as the case may be, I provide the valve 2? having a closure member 50 urged to closed position by an adjustable spring 51 acting through a stem 52 and acted upon by a diaphragm 53 which is subjected on its upper side to feed water valve outlet pressure and is subjected on its lower side to steam line pressure through the conduit 54 which is preferably connected into the steam line beyond the superheater. In other words, the pressure differential measured across the diaphragm 53 is a function of the boiler rating or load. The spring 51 may be set at any desired point to permit the closure member 50 to begin to move from its seat at any given load, and

thereafter to move greater distances from its seat as the load increases.

Presuming for a moment that the pilot valve rests on its lower seat, it will be appreciated that movement of the valve 27 will relieve the pressure below the piston 21 down to the point of substantially equalizing the pressures above and below the piston 21, depending on the amount of opening through the valve 27. In other words, regardless of the movement of the pilot valve 28 and regardless of changes in water level or in pressure variation in the generator 4, the closure member 10 of the feed water valve will be moved in response to changes in boiler rating through the operation of the valve 2'7 immediately upon a change in rating and possibly before the pressure generator responds or in spite of possible negative actions of the generator caused by surges in water level.

From the foregoing it will be seen that I have provided a system of feed water regulation embodied in a simple and rugged structure, which among other things is capable of performing the following functions: (first) a substantially constant flow of feed water is maintained, if desired, regardless of the variations in pump pressure or header pressure which cause a variation in pressure drop across the feed water valve; (second) the opening through the feed water valve while primarily established in response to changes in boiler water level or boiler conditions is secondarily established to compensate for changes in pressure drop across the valve; (third) the position of the feed water valve is also varied as may be desired in response to changes in boiler water level or boiler conditions to give a greater or less than normal opening throughout a range determined by the setting of the pilot valve; (fourth) the feed water valve will automatically assume wide open position by reason of the operation of the pilot valve to meet an emergency of low water; (fifth) the position of the, feed water valve will be varied in response to changes in steam flow or boiler rating and this effect will be added to the usual and normal positioning of the feed water valve which follow from changes in boiler water level and (sixth) all of these effects and agencies operate simultaneously and continuously throughout the operation of the boiler and are all subject to adjustment and correlation from time to time as the demand or occasion arises.

While the foregoing has been a description of a preferred form of an installation embodying my invention, I do not care to be specifically limited thereto or in' any manner other than by the claims appended hereto.

I claim:

1. A boiler feed water regulating valve having a closure member, means responsive to changes in boiler conditions for moving said closure member, and means comprising a piston connectedto said closure member subjected on one side to valve inlet pressure and on the other side to valve outlet for moving said closure member in response to changes in the pressure drop across said valve.

2. In a boiler feed water regulating valve the combination of means responsive to changes in boiler conditions for varying the opening of said valve, means responsive to changes in pressure drop across said valve for varying the opening therethrough and pressure actuated valve means responsive to changes in boiler conditions for modifying the action of said last named means.

3. In a boiler feed water regulating valve the combination of means responsive to changes in boiler conditions for varying the opening of said valve, means responsive to changes in pressure drop across said valve for varying the opening therethrough and means comprising a pressure actuated valve responsive to changes in boiler water level for modifying the action of said last named means.

4. In a feed water regulating valve having a closure member, the combination of means responsive to boiler conditions for moving said closure member, means for moving said closure member responsive to variations in fluid pressure drop across said valve, said means including. a piston connected to said closure member and subjected on one side to valve outlet pressure and subjected on the other side to valve inlet pressure and means for replacing or modifying the said valve inlet pressure on the last named side of said piston with various lesser pressures whereby said closure member may be moved to wide open position.

5. In a boiler feed system. a feed water valve, means for varying the opening of said valve according to changes in boiler conditions and additional means responsive to changes in boiler conditions for forcing said valve to an extreme position upon the occurrence of a predetermined boiler condition.

6. In a boiler feed water regulating valve, the combination of means responsive to changes in boiler conditions for varying the opening of said valve, means for modifying the opening of said valve inversely as a fluid pressure drop across said valve and pressure actuated valve responsive to changes in boiler water level for increasing the opening of said feed water valve irrespective of the action of said modifying means in the event the water level falls below a predetermined point.

'7. A boiler feed water regulating valve having a closure member, means for moving said closure member responsive to changes in water levelya piston connected to said closure member and subjected on one side to valve outlet pressure, a chamber on the other side of said piston, fluid conducting means leading from said chamber to the inlet side of said valve and valve means in said fluid conducting means responsive to changes in water level for controlling the flow of fluid in said conducting means and for varying the pressure in said chamber.

8. A boiler feed water regulating valve according to claim 7 wherein said fluid conducting means has a branch leading to a source of pressure lower than the valve inlet pressure and wherein means are provided forreducing the pressure in said piston chamber.

9. In a boiler feed water regulating valve, the combination of a pair of valves for varying the opening in said feed water valve according to changes in pressure drop across said feed water valve and means for varying the opening of one of said valves according to changes in boiler load.

10. In a boiler feed water regulating feed water valve, the combination of a pair of valves for increasing the opening of said feed water valve as the pressure drop across the valve decreases, and means for modifying the opening of said feed water valve as the boiler load increases.

11. In a boiler feed water regulating valve, the combination of means for increasing the opening of said valve as the pressure drop across the l-fiO valve decreases, means including a pressure actuated valve for. increasing the opening through said valve as the boiler load increases, and means for increasing the opening through said valve as the boiler water level lowers.

12. In a boiler feed water regulating valve, the combination of means for varying the opening of said valve in response to changes in boiler water level, auxiliary means for increasing the opening of said valve as the boiler water level lowers, means for decreasing the opening through said valve as the pressure drop across the valve increases and means for increasing the opening in said valve as the boiler load increases.

13. In a boiler feed water regulating valve, the combination of means tending to increase the opening through said valve when and as the boiler water level falls, means for increasing the opening through said valve when and as the boiler load increases and auxiliary means for further increasing the opening in the valve when the boiler water level falls to a predetermined point.

14. In a boiler feed water regulating valve, having a closure member the combination of a piston connected to said closure member having one side subjected to valve outlet pressure, said piston closing a chamber on the other side and being movable therein to move said closure member, fluid conducting means leading from said chamber to the inlet and outlet sides of said valve and valve means disposed in said fluid conducting means movable in response to changes in boiler load for controlling the flow of fluid in said fluid conducting means whereby changes in boiler load may cause the pressure on opposite sides of said piston to be substantially balanced.

15. In a feed water regulating valve having a closure member, the combination of resilient means tending to move said closure member to closed position, means responsive to a drop in water level for urging said valve toward open position, pressure actuable means connected to said closure member and subjected on one side to valve outlet pressure and thereby tending to move said closure member toward open position, said valve inlet pressure acting upon said last named means tending to move said closure member to closed position, said means closing one side of a fluid chamber within which fluid pressures developed tend to move said means and said closure member toward closed position, fluid conducting means leading from the inlet side of said valve to the outlet side of said valve and connected midway to said chamber, said fluid conducting means having a branch connection leading to atmosphere and valve means in said fluid conducting means responsive to changes in water level for varying the pressure in said chamber.

16. In a feed water regulating valve having a closure member, the combination of means responsive to a drop in water level for urging said valve toward open position, pressure actuable means connected to said closure member and closing one side of a fluid chamber within which fluid pressures tend to move said means and said closure member toward closed position, fluid conducting means leading from the inlet side of said valve to the outlet side of said valve and connected midway to said chamber, valve means in said fluid conducting means positioned between the outlet side of said valve and said chamber and responsive to changes in boiler output for varying the pressure in said chamber, and valve means positioned between the inlet side of said valve and said chamber and responsive to changes in boiler water level for varying pressure in said chamber.

17. A boiler feed water regulating valve having a closure member, means for moving said closure member responsive to changes in boiler water level, a piston connected to said closure member and subjected on one side to valve outlet pressure, a chamber on the other side of said piston, fluid conducting means leading from said chamber to the inlet side of said valve and valve means in said fluid conducting means responsive to changes in water level for controlling the flow of fluid in said conducting means and for varying the pressure in said chamber.

18. In a feed water regulating valve having a closure member, the combination of resilient means tending to move said closure member to closed position, means responsive to a drop in water level for urging said valve toward open position, pressure actuable means connected to said closure member and subjected on one side to valve outlet pressure and thereby tending to move said closure member toward open position, the valve inlet pressure acting upon said last named means tending to move said closure member to closed position, said means closing one side of a fluid chamber within which fluid pressures developed tend to move said means and said closure member toward closed position, fluid conducting means leading from the inlet side of said valve to the outlet side of said valve and connected midway to said chamber, said fluid conducting means having a branch connection leading to atmosphere and valve means in said fluid conducting means on opposite sides of said midway connection responsive to changes in boiler water level for varying the pressure in said chamber.

19. In a feed water regulating system, a feed water pipe having a valve therein, a boiler to which said feed water pipe leads, having a steam outlet pipe, a pressure generator connected to said boiler and spanning the normal water level thereof, pressure actuated means connected to said valve and to said pressure generator and being operable in response tochanges in pressure in said pressure generator, and means for actuating said valve in response to a pressure drop in said feed water line, including a conduit spanning the valve and connected to the feed water pipe on either side of the valve, a pair of pressure actuated valves in said pipe, one of said valves being actuatable in response topressures reflected in said pressure generator, the other of said valves being operable in response to pressures in said steam pipe.

HENRY J. MASTENBROOK. 

